Analysis of Linear FM Signal Based on the STFT in the Filtering Viewpoint

摘要

Analyzing signal with STFT in the angle of transformation is not able to achieve a fine resolution in both the time and frequency due to the restriction of the Heisenberg-Gabor inequality. However, little has been studied about the STFT in the filtering viewpoint, such as the influence of the length of the filter impulse response. This paper mainly studies the frequency estimation of linear frequency modulated (LFM) signal with the STFT in the filtering viewpoint. The length of the filter impulse response is observed in its impact on the variation of time-frequency distribution (TFD). Based on a series of experiments, it is proved that the longer impulse response does not always guarantee the better concentration in the TFD. To obtain the best TFD for the LFM signal processing, an optimal impulse response length needs to be determined beforehand.